Middlesbrough will look to uphold their recent giant-killing reputation after heading into the international break with two hard-earned away draws against title contenders Arsenal and Manchester City
Boro snatched a late point in the 1-1 draw at the Etihad two weeks ago in a resilient display that delighted boss Aitor Karanka. His men held their own and wore down a tiring City side, taking advantage of defensive slip-ups -- with Marten de Roon being in the right place at the right time to hammer home a bullet header from George Friend's pin-perfect cross in injury time. It was some praise after the game for City boss Pep Guardiola to say that it was easier to play against Barcelona than the chippy Teessiders.
All of the good stuff that we have seen lately seems to have stemmed from the shot in the arm that was Boro's trip to the Emirates back in late October. What may have felt like a fairly uneventful and forgettable 0-0 for Arsenal was a huge step for their opponents in terms of confidence and self-belief. In previous matches Boro were underwhelming, showing other teams far too much respect as if they almost didn't believe they warranted their place in the top division.
Coupled with the freedom in movement and fresh ideas brought from winger Adama Traore, a new lease of life was found and this vitality has carried Boro well through what looked on paper to be a tough run of matches. The point at Arsenal also buoyed Boro to get to grips with an in-form Bournemouth side who left the Riverside empty-handed after the sort of never-say-die performance that fans had been waiting weeks to see since last season's last-ditch promotion to the Premier League.
Concerns from the Chelsea camp around the fitness of key players Diego Costa and Eden Hazard are now allayed, not that Karanka would have changed his approach in any major way. For the Basque boss himself, he may choose not to start a couple of players who were on international duty last week, including influential midfield duo Gaston Ramirez and Cristhian Stuani, which means that Traore may earn himself another place in the starting line-up. Karanka is highly likely to persist with lacklustre striker Alvaro Negredo as a lone predator up front, the head coach continuing to bemuse fans at his refusal to give serial benchwarmer Jordan Rhodes a run in the side.
There are slight injury concerns around left-back George Friend, who has found a well-timed return to form after a shaky start to life in the Premier League. With key defender Dani Ayala ruled out for Sunday's tie, Boro will rely on the young pairing of Calum Chambers and the ever-impressive Ben Gibson to steady the ship against a highly threatening Chelsea attack.
The Blues are sitting pretty in second place, just a point behind Liverpool and also boast the best goal difference in the division. This shouldn't deter the Teessiders' in-form goalkeeper, Victor Valdes, who has enjoyed two clean sheets in three outings and will be disappointed with anything less than a continuation of his show-stopping form.
Most of the home faithful will see this game as a free pass -- after all, this is the type of tantalising clash that promotion promised -- and it's a welcome chance to see some of the world's greatest players on the Riverside pitch. Alongside Liverpool's visit in December, this is one of the hottest tickets for fans this side of the new year. Expectations will be managed but there will be a real sense of shame and disappointment if the Reds let all of their hard work and improvement from the last month or so begin to unravel.
After seven years away from the top flight, fans will be recalling classic ties against the Blues in both the league and also Boro's surprise FA Cup run back in the mid-90s that culminated in that Roberto Di Matteo goal on 42 seconds in the Wembley final. Antonio Conte is settling in well and the new Chelsea breed look like real contenders, but if the home side can pull out another gritty showing and Traore continues his magic moments, then anything could happen.